Hi. I heard the expression "make it count" in a movie, when two of the characters where having a fight. I was wondering what it means. Surly it's some-kind of threat, but I want to know what it exactly means.

If something counts, it means that it has importance, has significance, to what is happening in the context.

In the context of a fight, the idea is 'Try to hit him hard enough to win the fight'.

Thank you Clive! Now it makes more sense!